1. Technical Field
The present invention relates to a technology of driving a discharge lamp which emits light by discharge generated between electrodes.
2. Related Art
A projector provided with a discharge lamp is known. This type of projector supplies alternating power to the discharge lamp to generate discharge between two electrodes provided on the discharge lamp. In addition, such a technology is known which switches alternating power supplied to the discharge lamp from rated power to low power so as to increase life and decrease power consumption of the discharge lamp (see JP-A-2000-131668). The discharge lamp emits light by generating arc between projections formed on the respective electrodes.
According to the related-art technology discussed above, however, the quantity of fusion at the tips of the electrodes decreases when the discharge lamp is driven by power lower than rated power. In this case, projections having preferable shape are not formed, and thus arc flicker (hereinafter abbreviated as “flicker”) shifting the base point of arc may be produced. The flicker is more easily produced particularly immediately after power is switched to low power.